1. Field of the Invention
The present invention relates to a magnetic component including a magnetic core that includes a flange portion at each of opposite end portions of a winding shaft portion around which a conductive wire is wound, and a conductive terminal that includes a wire splicing surface for conductive wire connection, and a method for manufacturing such magnetic component.
2. Description of the Related Art
Conventionally, magnetic components such as disclosed in Japanese Laid-Open Patent Publication No. 2009-290093(A) are known. An example of this type of magnetic component is illustrated in FIGS. 7 and 8, and a conventional magnetic component will be described below with reference to these drawings. The illustrated magnetic component 110 includes a magnetic core 120, conductive terminals 130A and 130B and a coil 140.
As illustrated in FIG. 8, the magnetic core 120 includes a winding shaft portion 121 for conductive wire winding, and an upper flange portion 123 and a lower flange portion 125 provided on one end side of the winding shaft portion 121 (upper end side in the Figure) and another end side (lower end side in the Figure), respectively.
The terminals 130A and 130B each include an electrode portion 131 extending along a lower surface of the lower flange portion 125, and a wire splicing portion 133 extending from an end portion of the electrode portion 131. The electrode portion 131 is attached to the lower flange portion 125 so as to be in contact with the lower surface of the lower flange portion 125. The wire splicing portion 133 includes a part extending upward in the Figure (direction toward the upper flange portion 123), which is flexed at an angle of 90 degrees from the end portion of the electrode portion 131 (hereinafter this part is referred to as “erected portion”), and a part extending laterally (direction perpendicular to an axis of the winding shaft portion 121), which is further flexed at an angle of 90 degrees from an upper end portion of the erected portion (hereinafter this part is referred to as “laterally-flexed portion”), and an upper surface of the laterally-flexed portion includes a wire splicing surface 135 for conductive wire connection. These terminals 130A and 130B are each formed by flexing a metal plate material via, e.g., press working.
The coil 140 includes a conductive wire 141 wound around the winding shaft portion 121. Respective end portions 141a and 141b of the conductive wire 141 are connected to the respective wire splicing surfaces 135 of the terminals 130A and 130B via, e.g., thermal compression bonding or resistance welding.
FIG. 9 illustrates a schematic configuration when connecting the respective end portions 141a and 141b of the conductive wire 141 of the above-described magnetic component 110 to the respective wire splicing surfaces 135 of the terminals 130A and 130B via thermal compression bonding. The illustrated welding jig 170 is a jig having a general configuration, which is used when connecting end portions of a conductive wire in a conventional magnetic component such as the magnetic component 110 to wire splicing surfaces of terminals via thermal compression bonding.
As illustrated in the Figure, the welding jig 170 includes projection portions 171A and 171B. These projection portions 171A and 171B are provided to support the respective wire splicing surfaces 135 of the terminals 130A and 130B (the above-described laterally-flexed portions) from the lower side, which are pressed from the upper side in the Figure by a welding electrode 180, when connecting the respective end portions 141a and 141b of the conductive wire 141 to the respective wire splicing surfaces 135 of the terminals 130A and 130B via thermal compression bonding.
In order to connect the respective end portions 141a and 141b of the conductive wire 141 to the respective wire splicing surfaces 135 of the terminals 130A and 130B of the above-described conventional magnetic component 110 with good precision via thermal compression bonding, it is necessary that welding electrode 180 sufficiently press the respective wire splicing surfaces 135 of the terminals 130A and 130B while crushing the respective end portions 141a and 141b of the conductive wire 141 to a predetermined extent. In particular, where the magnetic component 110 is downsized so as to have external dimensions of around several millimeters, each wire splicing surface 135 is inevitably downsized, resulting in reduction in the area of the part to be welded, and thus, provision of a proper extent of crushing of the respective end portions 141a and 141b of the conductive wire 141 during thermal compression bonding is important for favorable connection of the conductive wire 141.
However, since the terminals 130A and 130B of the conventional magnetic component 110 are each formed by flexing a metal plate via, e.g., press working, large variations easily occur in a dimension in the height direction of the wire splicing portions 133. This is because not only errors caused by processing using, e.g., a pressing machine but also a tolerance in thickness of the metal plate affect the dimension in the height direction of the wire splicing portions 133.
Where large variations occur in the dimension in the height of the wire splicing portions 133, a fixed distance between a lower surface of the welding electrode 180 and each wire splicing surface 135 during thermal compression bonding cannot be maintained, making is difficult to provide a proper extent of crushing of the respective end portions 141a and 141b of the conductive wire 141, which may cause various types of failures. For example, if the extent of crushing is reduced, it may be impossible to provide sufficient connection strength, and conversely, if the extent of crushing is overly increased, the conductive wire 140 may be disconnected.
Also, a problem lies also in errors in dimension in the height direction of the projection portions 171A and 171B included in the welding jig 170. In other words, if the height of the projection portions 171A and 171B is smaller than a prescribed value, a distance ε between lower surfaces of the laterally-flexed portions of the terminals 130A and 130B and upper surfaces of the projection portions 171A and 171B is large. If the distances is excessively large, the laterally-flexed portions of the terminals 130A and 130B are pressed by the welding electrode 180 and thereby bent downward during thermal compression bonding, whereby the extent of crushing of the respective end portions 141a and 141b of the conductive wire 141 becomes small, which may result in impossibility to provide sufficient connection strength. Conversely, if the height of the projection portions 171A and 171B is larger than the prescribed value, a position in height direction of the wire splicing surfaces 135 is raised, whereby the extent of crushing of the respective end portions 141a and 141b of the conductive wire 141 during thermal compression bonding becomes too large, which may cause disconnection of the conductive wire 140.